Selective preservation of coleoid soft tissues in Lebanese Konservat-Lagerstätten

Abstract The Upper Cretaceous Konservat-Lagerstätten of Lebanon—the Santonian-aged Sahel Aalma (Sahel Alma), and Cenomanian-aged Hjoula (Hadjoula, Hgula) and Haqel (Hakel, Haqil)—are world-renowned for their exceptional preservation of fossil organisms. Taphonomic studies are still quite rare at these sites and have typically focused either on preservational differences between organisms or comparisons with other Konservat-Lagerstätten. Questions regarding preservational variation (whether each locality in these limestones preserves the same tissues, with the same composition, and at the same high level of occurrence, for example) have yet to be answered. Such preservation variability has implications for a variety of palaeontological analyses, including systematics, phylogenetic character coding, and palaeoecological interpretation. Here, we combine multiple imaging techniques to explore the preservation of a large sample of a single cephalopod species, Dorateuthis syriaca (n = 71). This taxon (order Octobrachia) occurs in abundance at each of the three main gladius-bearing coleoid localities and spans c.10 Ma. The observed presence or absence of tissues and organs was used to constrain the preservation potential in each of the localities, and further statistical analyses were conducted to identify if differences between localities were significant. Our results show that Haqel and Hjoula are likely to preserve more soft tissues than Sahel Aalma, mainly due to a higher occurrence of circulatory and respiratory tissues. These data highlight the need to focus on local locality conditions when studying exceptional preservation, despite the limestone composition of each of the Konservat-Lagerstätten.